1. Field of the Invention
The present invention relates to a needle threader for facilitating the insertion of a thread into the eye of a needle.
2. Description of the Related Art
A conventional needle threader is disclosed in JP Laid-open No. 2000-51561, for example. As shown in FIG. 15 of the accompanying drawings of the present application, the conventional needle threader includes two needle holders 91 provided on the main body 90. Each needle holder 91 has a trunk 91b formed with a needle receiving hole 91a for insertion of a needle 8. On a prescribed side of the trunk is provided a groove 92 for positioning a thread T. The main body 90 is provided with an operating member 93 and a pair of pushers 94. When the operating member 93 is pushed down in the direction shown by an arrow Na, each of the pushers 94 rotates about a shaft 95 in the direction shown by an arrow Nb, and advances towards the needle holder 91. Consequently, as shown in FIG. 16, the thread T is pushed by the pusher 94 to pass through the eye 80 of the needle 8.
While being functional in several respects, the conventional needle threader suffers the following drawbacks.
Generally, sewing needles come in various sizes, and the location and size of the needle eyes usually differ. Specifically, as shown in FIG. 17, a diametrically small needle 8A tends to have a small eye 80A, and the distance s1 between the head end and the eye 80A is short. On the other hand, a diametrically greater needle 8B may have a large eye 80B, and the distance s2 between the head end and the eye 80B is relatively long.
In the prior art, the forward path of the pusher 94 to push the thread T toward the needle holder 91 is permanently fixed. Thus, the insertion of the thread into the eye 80 may fail if a change is made in the height of the eye 80 of the needle 8 set in the needle holder 91.
In light of the above, the prior art is provided with two sets of threading mechanisms each including the combination of a pusher 94 and a needle holder 91, one set being arranged for a thick needle, and the other for a thin needle, so that either one of the needles is properly threaded.
However, providing a plurality of threading mechanisms increases the number of components in the threader as a whole, thereby complicating the overall structure and resulting in a higher production cost. Also, it allows the threader to become bulky and renders inconvenient to be stored or carried. Further, in case where a small needle is inserted into the larger needle holder by mistake, the thread cannot be passed through the needle""s eye, which forces the user to reset the needle into the other needle holder for thinner needles. Particularly, since the user has difficulties in deciding which one of the needle holders 91 is suitable for a needle to be threaded, the above troublesomeness becomes more conspicuous.
The present invention has been proposed under the circumstances described above. It is, therefore, an object of the present invention to provide a needle threader that can deal with needles of various sizes, with a single or reduced number of threading mechanisms, whereby the overall structure is simplified and the convenience is improved.
According to the present invention, there is provided a needle threader comprising: a needle holder for holding a needle; and a pusher for inserting a thread into an eye of the needle, the pusher being movable in a forward direction toward the needle holder and in a backward direction opposite to the forward direction. The pusher is movable longitudinally of the needle while the pusher is held in sliding contact with the needle.
Preferably, the needle threader of the present invention may further comprise a pusher guide for guiding the pusher, wherein the pusher guide changes its position for causing the pusher to move longitudinally of the needle.
Preferably, the needle threader of the present invention may further comprise a working mechanism provided with an operation lever for operating the pusher, wherein the operation lever continues to be operated after the pusher comes into contact with the needle, so that the pusher guide causes the pusher to move longitudinally of the needle.
Preferably, the needle threader of the present invention may further comprise an elastic member arranged between the operation lever and the pusher. The elastic member permits further operation of the operation lever after the pusher is brought into contact with the needle.
Preferably, the needle holder may comprise a needle receiving hole for vertically holding the needle. The needle holder may be formed with a pusher path extending across the needle receiving hole for allowing the passage of the pusher across the needle receiving hole.
Preferably, the pusher path may be large enough to allow the pusher to move longitudinally of the needle.
Preferably, the pusher may undergo a first forward move and a second forward move subsequent to the first forward move. The pusher may advance horizontally from an initial position to the needle during the first forward move, while the pusher may ascend during the second forward move.
Preferably, the pusher may undergo a first backward move subsequent to the second forward move and a second backward move subsequent to the first backward move. The pusher may retreat horizontally during the first backward move to pull out of the eye of the needle, while the pusher may descend during the second backward move to return to the initial position.
Preferably, the needle threader of the present invention may further comprise a needle presser that is horizontally reciprocative for selectively pressing the needle against a wall surface of the needle receiving hole.
Preferably, the pressing of the needle by the needle presser may be performed before the pusher comes into contact with the needle.
Other features and advantages of the present invention will become apparent from the detailed description given below with reference to the accompanying drawings.